Bottom plate fixing device for a switchgear cabinet

ABSTRACT

A bottom plate fixing device for a switchgear cabinet, whereby an edge of at least one bottom plate is placed on a support flange of a bottom frame of the switchboard cabinet and is preloaded by at least one fastening clip. The clip has two parallel legs which are held on a connecting section, whereby the first leg engages behind the support flange of the bottom plate and the other leg holds a screw in a thread. The screw can be tightened against the edge of the bottom plate. The bottom plate and the bottom frame can be reliably placed on the same electrical level by supporting the first leg on the support flange by cutting and/or sharpening contact elements, and such that the screw is in electrically conductive contact with the edge of the bottom plate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a fastening for a bottom plate of a switchgearcabinet, wherein an edge of at least one bottom plate is placed on asupport flange of a bottom frame of the switchgear cabinet and isclamped together with at least one tightening clamp, wherein thetightening clamp has two legs which are parallel with each other and areheld on a connecting section, wherein the first leg grasps the supportflange of the bottom from behind, and wherein the other leg holds ascrew in a thread, which can be tightened against the edge of the bottomplate.

2. Description of Prior Art

Such a bottom plate fastening is known from German Patent Reference DE44 46 223 C1. The bottom frame of the switchgear cabinet is assembledfrom four profiled sections. The profiled sections are essentiallyembodied in a U-shape, wherein two vertically projecting profiled sidesare connected to a horizontal support section. The edges of the profiledsides are beveled. A horizontal support flange is thus created on theprofiled section located in the interior, on which bottom plates can belaid flat. The edges of the bottom plates can be connected with thesupport flange with tightening clamps. The tightening clamps aredesigned as U-shaped components with two parallel legs.

The edge and the support flange are located between the two legs. One ofthe legs has a screw, by which the bottom plate can be clamped togetherwith the support flange on the second leg.

SUMMARY OF THE INVENTION

It is one object of this invention to produce a fastening of the typementioned at the outset, wherein the bottom plate and the bottom framecan be dependably placed on a same electrical level.

This object is achieved with a first leg supported by bezels and/or tipsof contacting elements on the support flange, wherein the screw is in anelectrically conducting contact with the edge of the bottom plate.

When the tightening clamp is tightened, the bezels and/or tips dig intothe support flange. In particular, a layer of lacquer on the supportflange can be penetrated, to assure electrical contact between thetightening clamp and the support flange. The electrically conductingconnection with the bottom plate is produced via the screw. When screwedin, the screw contacts the bottom plate. Because of tightening of thescrew, the screw rubs across the surface of the bottom plate and thus isable to create an assured electrical contact.

In accordance with a preferred embodiment of this invention, at leasttwo contacting elements, which are embodied as tongues, are stamped outof the first leg and are bent in a direction toward the support flange.The ends of the tongues are cut off transversely with respect to theirlongitudinal sides, so that bezels are formed. A cost-effectiveproduction of the tightening clamps is possible with this simple step.

Stiffening of the tightening clamps is achieved if the connectingsection has reinforcement ribs, which extend vertically in relation tothe legs. Thus the connecting section is not bent when the screw istightened.

Also, the reinforcement ribs extend past the edge areas formed betweenthe connecting section. This simple step prevents the legs from beingbent open when the tightening clamp is tightened. Large clamping forcescan be transferred to the bottom plate and the support flange by such arigid tightening clamp.

In another embodiment of this invention, the tightening clamp is formedin a U-shape from a stamped bent component, and the leg facing thebottom plate has a bulge-like thickened place into which the screwreceptacle for the screw is cut. It is thus possible for the tighteningclamp to be made of a relatively thin sheet metal material. A sufficientlength of the screw thread is assured due to the thickening.

The front of the screw can have protrusions for an improved electricalcontact between the bottom plate and the screw. These dig into thesurface of the bottom plate when the screw is tightened.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be explained in greater detail in view of anexemplary embodiment represented in the drawings wherein:

FIG. 1 is a cross-sectional side view of a tightening clamp with ascrew;

FIG. 2 is a perspective view of the tightening clamp shown in FIG. 1;and

FIG. 3 is a cross-sectional view of the tightening clamp shown in FIGS.1 and 2, in a mounted position.

DESCRIPTION OF PREFERRED EMBODIMENTS

A tightening clamp 10 is shown in FIG. 1, which is essentially U-shapedfrom a connecting section 13 and two legs 11, 12 connected with it,which are parallel with respect to each other. Here, the upper leg 11has a bulge-like thickening 15. A threaded receptacle passes through thethickening 15. In this case the axis of the thread extends verticallywith respect to the leg 1. A screw 17 can be screwed into the threadedreceptacle. The lower leg 12 has three contacting elements 16. Detailsof the arrangement of the contacting elements are shown in FIG. 2. Thecontacting elements are stamped in a tongue-like manner out of the leg12. In this case the ends of the contacting elements are cut offobliquely to their longitudinal direction, so that triangular tipsresult. In the area of their tips, the contacting elements 16 are bentin the direction toward the upper leg 11. Sharp-edged bezels of thecontacting elements 16 project into the receiving space surrounded bythe tightening clamp 10. The tightening clamp 10 has three contactingelements 16. The center contact element 16 is aligned with the centerlongitudinal axis of the screw 17. The front of the screw can haveprotrusions for an improved electrical contact between the bottom plateand the screw. The protrusions dig into the surface of the bottom platewhen the screw is tightened.

Reinforcement ribs 14 stiffen the tightening clamp 10. The reinforcementribs 14 extend vertically with respect to the legs 11, 12 over theentire height of the connecting section 13. Adjoining the connectingsection 13, the ribs 14 are conducted over the edge area resultingbetween the connecting section 13 and the legs 11, 12, and partiallyextend over the legs 11, 12. The reinforcement ribs 14 are in the formof moldings, which are pressed out of the material of the tighteningclamp 10.

An exemplary application of the tightening clamp 10 of this invention isshown in FIG. 3. A bottom frame 20 is shown in this drawing, which has ahorizontal support section 21. Two profiled sides 22, 23 are bent atright angles off this support flange 21. A support flange 24 is bent offthe inner profiled side 23. An edge of a bottom plate 25 can be placedon the support flange 24. The bottom plate 25 can be clamped togetherwith the support flange 24 by means of several tightening clamps 10. Inthis case the U-shaped tightening clamp is mounted in such a way thatthe edge of the bottom plate 25 and the support flange 24 rest betweenthe two legs 11, 12. When the screw 17 is tightened, the bottom plate 25and the support flange 24 are pressed against contacting elements 16, asshown by the dashed lines of the screw 17, in FIG. 3. Because the screw17 is charged with a clamping force, the bezels of the contactingelements 16 dig into the underside of the support section 24. Anelectrically conducting connection is thus made between the tighteningclamp 10 and the bottom frame 20. At the same time the screw 17 isplaced on the electrically conducting upper surface of the bottom plate25, so that an electrical connection is also generated there. Thus thebottom plate 25 and the bottom frame 20 are placed on the sameelectrical potential.

What is claimed is:
 1. In a fastening for at least one bottom plate of aswitchgear cabinet, wherein an edge of the at least one bottom plate isplaced on a support flange of a bottom frame of the switchgear cabinetand is clamped together with the support flange by at least onetightening clamp, wherein the at least one tightening clamp has two legsparallel with each other and held on a connecting section, wherein afirst leg of the legs grasps the support flange, and wherein a secondleg of the legs holds a screw in a thread, wherein the screw can betightened against the edge of the bottom plate, the improvementcomprising: the bottom plate and the support flange having contactingsurfaces which are parallel to each other and parallel to the parallellegs of the tightening clamp, the first leg (12) supported by at leastone of a plurality of bezels and a plurality of tips of a plurality ofcontacting elements (16) on the support flange (24); at least two of thecontacting elements (16) embodied as tongues and stamped out of thefirst leg (12) and bent in a direction toward the support flange (24),and ends of the tongues cut off transversely with respect tolongitudinal sides of the tongues so that the bezels are formed; and thescrew (17) in an electrically conducting contact with the edge of thebottom plate (25) and the plurality of tips in an electricallyconducting contact with the support flange (24), the tightening clampand screw being conductive, thereby placing the bottom plate and thesupport flange at the same electrical level.
 2. In the fastening for theat least one bottom plate in accordance with claim 1, wherein theconnecting section (13) has reinforcement ribs (14) which extendvertically with respect to the legs (11, 12) over the connectingsection.
 3. In the fastening for the at least one bottom plate inaccordance with claim 2, wherein the reinforcement ribs (14) extendbeyond edge areas formed between the connecting section (13) and thelegs (11, 12).
 4. In the fastening for the at least one bottom plate inaccordance with claim 3, wherein the tightening clamp (10) is formed ina U-shape from a sheet metal stamped bent component, and the second leg(11) facing the at least one bottom plate (25) has a bulge thickening(15) into which a screw receptacle for the screw (17) is cut.
 5. In thefastening for the at least one bottom plate in accordance with claim 4,wherein the screw (17) has protrusions on a front end of the screw (17)which is positioned on the bottom plate (25).
 6. In the fastening forthe at least one bottom plate in accordance with claim 1, wherein thetightening clamp (10) is formed in a U-shape from a sheet metal stampedbent component, and the second leg (11) facing the at least one bottomplate (24) has a bulge thickening (15) into which a screw receptacle forthe screw (17) is cut.
 7. In the fastening for the at least one bottomplate in accordance with claim 1, wherein the screw (17) has protrusionson a front end of the screw (17) which is positioned on the bottom plate(25).
 8. In a fastening for at least one bottom plate of a switchgearcabinet, wherein an edge of the at least one bottom plate is placed on asupport flange of a bottom frame of the switchgear cabinet and isclamped together with the support flange by at least one tighteningclamp, wherein the at least one tightening clamp has two legs parallelwith each other and held on a connecting section, wherein a first leg ofthe legs grasps the support flange, and wherein a second leg of the legsholds a screw in a thread, wherein the screw can be tightened againstthe edge of the bottom plate, the improvement comprising: the bottomplate and the support flange having contacting surfaces which areparallel to each other and parallel to the parallel legs of thetightening clamp, the first leg (12) supported by at least one of aplurality of bezels and a plurality of tips of a plurality of contactingelements (16) on the support flange (24), the at least one of aplurality of bezels and an plurality of tips being formed from the firstleg and bent in a direction towards the support flange, and the screw(17) in an electrically conducting contact with the edge of the bottomplate (25) and the plurality of tips in an electrically conductingcontact with the support flange (24), the tightening clamp and screwbeing conductive, thereby placing the bottom plate and the supportflange at the same electrical level; and reinforcement ribs (14)extending vertically with respect to the legs (11, 12) over theconnecting section.
 9. In the fastening for the at least one bottomplate in accordance with claim 8, wherein the reinforcement ribs (14)extend beyond edge areas formed between the connecting section (13) andthe legs (11, 12).
 10. In the fastening for the at least one bottomplate in accordance with claim 8, wherein at least two of the contactingelements (16) are embodied as tongues and are stamped out of the firstleg (12) and are bent in a direction toward the support flange (24), andends of the tongues are cut off transversely with respect tolongitudinal sides of the tongues so that the bezels are formed.
 11. Inthe fastening for the at least one bottom plate in accordance with claim8, wherein the tightening clamp (10) is formed in a U-shape from astamped bent component, and the second leg (11) facing the at least onebottom plate (24) has a bulge thickening (15) into which a screwreceptacle for the screw (17) is cut.
 12. In the fastening for the atleast one bottom plate in accordance with claim 8, wherein the screw(17) has protrusions on a front end of the screw (17) which ispositioned on the bottom plate (25).